Plant Redesign Research Articles

Plant Redesign for pH Neutralization Process of Textile Wastewater Treatment

This study reports the redesign of a laboratory-scale pilot plant for textile wastewater treatment, especially in the pH neutralization process. The goal was to improve the plant structure, to facilitate more efficient process control. The result was a modular wastewater treatment plant that easy to operate and more efficient. A microcontroller controlled the plant. The plant was equipped with sensors and actuators to enable process monitoring and control in real-time. The control system was able to maintain the waste pH close to the setpoint (pH 8.5) despite the process disturbances.

Water conservation in beverage production: examining corporate water stewardship programs

This paper evaluates the effectiveness of the current water conservation methods of beverage companies and provides suggestions for beverage companies on bet water stewardship strategies. In this paper, I answer two research questions: what are beverage companies’ water conservation strategies? What are the results, and how are the results measured? Four case studies on leading beverage companies are presented. The strategies are categorized by their contributions to different phases of production: the pre-production process, the production process, and the post-production process. Methods in the pre-production process concentrate on sustainable agriculture because agriculture consumes the most amounts of water resources. Strategies in the production process are operation management and plant redesign because they can effectively reduce water consumption in manufacture. The most popular approach in the post-production process is partnering with an environmental organization because it can influence the most amount of people. The four companies’ empirical experiences provide other beverage companies with lessons on sustainable water consumption and reveal practical directions for future academic researches.

Hybrid approach of discrete event simulation integrated with location search algorithm in a cells assignment problem: a case study

This paper presents a case study describing a cell assignment problem in an assembly facility. These cells receive parts from external suppliers, and sort and sequence these parts to feed the final assembly line. Therefore, to each cell are associated important inbound and outbound flows generating hundreds of material handling equipment movements along the facility, impacting the traffic density and causing eventually safety issues in the plant. Following an important plant redesign, cells have been relocated, and the plant managers need to decide how to manage the new logistic flows. To that aim, a hybrid approach encompassing mathematical optimization and discrete event simulation (DES) is proposed. This approach allows us to reduce complexity by decomposing the design into two phases. The first phase deals with the problem of generating cell’s assignment alternatives by using a heuristic method to find good quality solutions. Then, a DES software is used to dynamically evaluate the performance of the solutions with respect to operational features such as traffic congestion and intensity. This second phase provides interesting managerial insights on the manufacturing system from both quantitative and qualitative aspects related to in-plant safety and traffic.

The impact of a participatory ergonomics intervention: the value of involvement

ABSTRACTThis article presents the implementation of a participatory ergonomics (PE) approach in a multinational company in the northern side of Italy, aiming to improve ergonomics, well-being and production outcomes. The methodology used is based on the creation of a multi-disciplinary team to provide and discuss ergonomics’ solutions according to the physical problems of the workers involved and better manage the re-introduction of the workers in the line of production. The study consists of a longitudinal analysis before and after the plant redesign and the PE intervention. Some psychosocial variables as job satisfaction, perceived fatigue, perceived usefulness, repetitiveness, occupational safety and company attention to safety have been monitored to verify the impact of the PE intervention. The results show how the PE intervention positively influences the perception of workers regarding the level of fatigue and repetitiveness and increasing job satisfaction, usefulness and occupational safety with a positive impact on productivity.

Multi-objective optimisation of wastewater treatment plant control to reduce greenhouse gas emissions

This study investigates the potential of control strategy optimisation for the reduction of operational greenhouse gas emissions from wastewater treatment in a cost-effective manner, and demonstrates that significant improvements can be realised. A multi-objective evolutionary algorithm, NSGA-II, is used to derive sets of Pareto optimal operational and control parameter values for an activated sludge wastewater treatment plant, with objectives including minimisation of greenhouse gas emissions, operational costs and effluent pollutant concentrations, subject to legislative compliance. Different problem formulations are explored, to identify the most effective approach to emissions reduction, and the sets of optimal solutions enable identification of trade-offs between conflicting objectives. It is found that multi-objective optimisation can facilitate a significant reduction in greenhouse gas emissions without the need for plant redesign or modification of the control strategy layout, but there are trade-offs to consider: most importantly, if operational costs are not to be increased, reduction of greenhouse gas emissions is likely to incur an increase in effluent ammonia and total nitrogen concentrations. Design of control strategies for a high effluent quality and low costs alone is likely to result in an inadvertent increase in greenhouse gas emissions, so it is of key importance that effects on emissions are considered in control strategy development and optimisation.

Engineering system co-design with limited plant redesign

Rather than designing engineering systems from the ground up, engineers often redesign strategic portions of existing systems to accommodate emerging needs. In the redesign of mechatronic systems, engineers typically seek to meet the requirements of a new application via control redesign only, but this is often insufficient and physical system (plant) design changes must be explored. Here, an integrated approach is presented for the redesign of mechatronic systems involving partial plant redesign that avoids costly complete redesign. Candidate plant modifications are identified using sensitivity analysis, and then an optimization problem is solved that minimizes redesign cost while satisfying system requirements. This formal methodology for Plant-Limited Co-Design (PLCD) is demonstrated using a robotic manipulator design problem. The PLCD result costs significantly less than the full redesign, and parametric studies illustrate the tradeoff between redesign cost and performance. It is shown that the proposed sensitivity analysis results in the lowest cost limited redesign.

Early Stage Process Controllability Assessment

Publisher Summary This chapter discusses the controllability of process design for designing a plant. Traditionally, process design has concentrated on the design of a plant intended to operate at a set of well defined flow-sheet conditions. This has tended to result in the problem of how to achieve and maintain these flow-sheet conditions being postponed to the later stages in the design process· This sequential approach to system design can result in plants which are difficult to control. Often, remedial work has to be done, post start-up, for the plant to achieve its control objectives. In extreme cases, the plant dynamics have been so difficult that plant redesign has had to be done to enable it to run successfully. The pressures to reduce capital cost and plant inventories together with the need for flexible operation mean that this approach are no longer acceptable. To enable early consideration of control the process, engineer requires a set of simple control indicators which are easily understood by non control engineering specialists.

The material composition of product and new materials

The material composition of product is defined as the quantity of a material used in the production of one unit of a product during a year. This ratio is computed by dividing the quantity of goods produced duting that year, and has shown steady declines over time for many metals. These declining trends could be the result of several interrelated effects: the substitution of other materials, continued improvements in product design, and improvements in manufacturing technology. This paper demonstrates that these effects can be classified into two categories. First, existing products and manufacturing processes can be improved and made more material efficient. This is a short-run adjustment bucause no major changes are made to capital equipment. This adjustment process can be modelled by the use of learning curves. The second category of changes that allow adjustments in materials manufacturing plant redesign. This requires major capital investment to re-tool the manufacturing process and is therefore a long-run adjustment that can be characterizedby models of the diffusion of new tehnology. These two aspects (short-run learning curves and lon-run trends in the diffusion of technology) are demonstrated for the case of the materials used in manufacturing beer containers in the USA.

Plant Design and Plant Automation Uses for Digital Computer Simulations

This paper provides an introduction to the use of simulation as it is related to industrial plant design and industrial automation. The project, technical and programming requirements for producing an operational plant simulation, economic and environmental extensions of the plant simulation, application for these simulations in new plant design and older plant redesign, and the importance of these simulations to achieving efficient and profitable plant automation are discussed. The state-of-the art in the industrial application of simulation technology is reviewed.